Steam-generator



(No Model.) 2 Sheets-*Sheet l.

D BIRDSALL. STEAM GENERATOR.

Patented June 12, 18,94..

'me NA'noNAL urnes-Mmmm COMPANY.

(No Model.) 2 sheets--sheet 2. D. BIRDSALL.

STEAM GENERATOR. No.521,32'9. Patented June 12, 1894.

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DAVID BIRDSALL, OF JERSEY CITY, NEW JERSEY.

STEAM-GENERATOR.

SPECIFICATION forming part of Letters Patent. No. 521,329, dated J une12, 1894:.v

Application tiled April 17, 1893. Serial No. 470,650. (No model.)

, connected with the back vertical portion of the boiler .or generatorand its upper ends w1th a horizontal front portion; and the inventionconsists in the peculiar construction,

arrangement and combinations of parts hereinafter more particularlydescribed and then definitely pointed out in the claims.

In the accompanying drawingse-Figure l is alongitudinal vertical centralsection of a generator and furnace constructed according to myimprovement. Fig. 2* is a partly sectional front view, the section beingtaken on the line az, Fig; 1. Fig. 3 is a horizontal section on the line'y y in Fig. l. Fig. 4. is an end view, with the rear of the casingremoved. Fig. 5 is a detail on a larger scale, which will be more fullydescribed hereinafter.

o Referring now to the details of the drawings by lettere-A representsthe main generating tubes which are curved as shown and set into top andback headers B B', preferably by means of an ordinary tube expandingtool. These tubes are arranged compactly7 1n a series of rows, and areso set that each inner tube of one row will be over the space betweentwo tubes of the row below it, as will be clearly seen in Figs. 2 an 4.

The headers B B are tubular in form and of cast metal, preferably ofsteel, the upper or front series B being similar to the rear series B',except that in addition to the openings to receive the generating tubes,they have additional openings to receive the return water pipes C. Theheaders are of a length corresponding to the width of the generator andare provided with openings b surrounded by langesh at 'each end, bywhich they may be secured together by bolts Z2 passing through holes b3in the iianges b', and are arranged one above the other in the rearseries, or horifwhich openings are closed by Stoppers b5.

C are the return water pipes inserted near 6o each end of the upperheaders and lead downward and into the base circulating pipesD D.

D D represent two strong tubes of wrought iron or steel extendinglongitudinally on each side respectively, and serve as a base for thegenerator as well as a conduit for the water o iiowing through the tubeC toward the back series of headers.

At E are shown two short pipes which complete the connection between thelbase pipes 7o D and D and' the back headers, and at F are two pipeswhich connect the upper series of headers with the steam drum andprovide for the free passage of steam to the drum I, where it collectsfor use.

At Gis a pipe, the end 0f which projects into the bottom of steam drum Ifor a short distance, and by means of right and left hand branches g gconnects with the top of the back series of headers, thereby providingfor 8o the retention of a small quantity of water in the bottom of thedrum where the same is exposed to the heat ot the furnace gases, and forthe ilow by gravity of the surplus water into the back headers, and themaintenance of the water equilibrium iii the generator thereby. By meansof this connection in combination with the steam pipe F F the drumI isrigidly held in position.

There is a short tubular connection H, be- 9o tween the back ends ofpipes D D', which by means of elbows is carried down to a lower level,.and serves the purpose of a sediment trap 'into which all earthydeposits from the water fall, and should be provided with the usual`cock H' by which the sediment may be blown 0E. v

.T J are detiecting plates arranged across the combustion chambers fromside to side, back of the bridge wall and are provided loo with holesfor the passage of the tubes, 85o. These plates serve to arrest thedirect flow of the incandescent gases to the chimney and vdirect them ina tortuous course around the V tubes.

generator tubes until the heat of the gases shall have been absorbed.Plate J rests on the top of the bridge wall K and extends upward,inclining toward the front up to the upper row of tubes, which defiectsthe hot gases upward into the chamber above the Plate J is arranged somedistance back of plate J and leads from the lower surface of the drum Idownward to near the lowermost row of generator tubes, thereby arrestingthe direct flow of hot gases to the chimney, and leading them in thedirection shown by the dark arrows in Fig. l. These plates J J arecomposed of thin sheets of iron upon each side of which is cemented athin coating of asbestus fiber or other refractory material, therebyprotecting the central sheet of iron from speedy destruction.

N N represent walls of fire brick which inclose the lower` part of thefurnace on the front and on each side back to the bridge wall. The sideWalls are built inside of the vertical tubes C and rest upon plates Owhich are riveted to the outer covering, and extend upward only abouttwo feet, so as to inclose the hottest part of the furnace.

At P is shown the casing which completely incloses the curved tubes oneach side and on the front, from thewalls N upward to the upper headersand steam drum. This casing isof similar construction to the defiectingplates J J and is adapted to retain the heat within the furnace and tubechamber.

The back system of headers when bolted together and in position servesas the rear wall of the furnace, and the upper system of headers servesa like purpose for the upper front of the same.

The rear part of the combustion chamber above the horizontal part of thegenerator tubes is mostly covered by the steam drum as before mentioned,and which in combination with suitable connecting casing finally guidesthe spent gases up the chimney Q.

R represents an outer casing of thin sheet iron which incloses thegenerator on all sides, leaving an intermediate air space which reducesthe escape of heat to a minimum.

U U indicate pipes leading from the water pipe D' and from the steamdrum, respectively, and terminate in the proper fittings to receive theends of the water gage V.

W, Fig. 5, shows a thimble which is inserted in the back ends of thegenerator tubes for the purpose of reducing the flow of Water throughthe same, thereby preventingthe flooding of the upper headers withwater, it being desirable to permit only the admission of such aquantity as shall supply an excess above the steam generating capacityof each tube, sufficient to prevent the formation of sedimentary scaleon their inner surfaces.

The furnace is provided with the ordinary grate bars K and furnace doorY, and the boiler should of course be provided with an injector or feedpump, and the drum should have the usual safety valve, an outlet for thesenses steam, and a valve closing it,but as these are common there is nonecessity for further description of the same.

Having now described the construction of my generator, I will nowproceed to explain its operation.

The generator having been filled in any suitable manner until the waterin the gage has risen about halt' way to the top, I then start a fire inthe furnace in the usual manner, and the heat of the furnace at oncebegins to act upon the Water in the generator tubes, while the hotgases, as they give off their heat, [low in the direction shown by thelong arrows in Fig. 1, upward and around plate .I and under plate J',finally escaping up the chimney. Very soon after the fire has beenstarted, the small amount of water contained in the tubes begins to boiland the steam thereby gener ated will at once flow by way of thevertical portion of the tubes, as in this direction 1t encounters theleast resistance. The steam thus formed passes into the upper headersand thence flows into the end passages common to the whole series, andthen by way of pipes F to the steam drum. As soon as the heat of thefurnace increases and a violent generation of steam commences along theentire length of the tubes, the escaping steam will carry along in itscurrent a considerable volume of water and project it into the upperheaders. As this water cannot return against the constant rush of steamup the generator pipes, it flows toward the ends of each headerrespectively and falls through pipes C into base pipes D and D andthence into the back headers. By means of this provision for the freeseparation of the steam from the water in the upper headers, the steamflows to the drum nearly free from globules of Water. As soon as theWater in the generator tubes begins to be exhausted in the process ofgenerating steam just described, more water iows in from the back headersystem by way of the contracted openings in the back ends of thegenerator tubes. A constant and rapid circulation of water is thus keptup throughout the whole system of tubes, pipes and headers, with avelocity in proportion to the intensity of the fire maintained in thefurnace. Thelong vertical curve of the generatortubes directly above thehottest part of the furnace greatly accelerates the circulation of thewater in said tubes and consequently greatly increases the steamgenerating capacity of the same. This rapid circulation also pre ventsthe lodgment of sedimentary scale upon their inner surfaces and therebyavoids the principal cause of the destruction of the tubes by burning aswell as of diminution of steam generating efficiency. All earthymatters, lime and magnesian deposits which enter the generator with thefeed water are kept by this rapid movement from finding a lodgment uponthe internal surfaces exposed to the action of external heat whereby itmay become fixed. The sedimentary matter be- IOO IIC

f furnace is raised to a high degree and the tubes D D, the sedimentfalls by gravity' downward and into cross pipe H from whence it may beblown out in the form of mud at any time as may be required. The waterrising through pipes C will be comparatively free from sediment so longas the deposit constantly filling the pipe I-l is kept blown off and thewater circulating through the system above kept from becomingovercharged with earthy matter. When the heat of the steam generatingcapacity approaches the maximum, globules of water are carried over intothe steam drum and collect in the lower part of the same, but as soon asthe accumulation shall reach the level of the projecting end of drainpipe G, it falls by gravity into the back system of headers bymeansplainly shown in Fig. 4f. The facility and rapidity with which the watercarried u p into the front headers in the process of steam generation,returns lo its normal level, prevent the fluctuation of equilibrium sooften shown by the water gage in generators of this type.`

As the circulation in each one of the generator tubes is independent ofeach and all of the other tubes, the vcirculation within all beingtoward the upper headers, there is no action known as steam binding inthis generator, as is often shown by the internal disturbances andshocks occurring in generators composed of horizontal tubes connectedbetween vertical tiers of headers, front and rear.

Owing to the small cross section of the generator tubes, and the Verylarge amount of heating surface which this system makes it possible tocrowd into a small furnace space, steam can vbe raisedA to a highpressure in a short time, which makes this generator especially adaptedfor use en shipboard where lightness and safety are of primeconsideration. Also by reason of the small cross section ot' its tubesand connections, it will withstand an exceptionally high internalpressure with safety, thusadapting it tothe most modern requirements.

This generator can be made ot any capacity up to hundreds of horse-powerby simply lengthening-the design of the headers which correspond to thewidth of the generator, furnace, dac.

There are no joints exposed to the destructive action of the heat of thefurnace, and the curve in the generator tubes leaves freedom to theinfluence of expansion and contraction, and consequently prevents thespringing and other derangements so common in other generators.

I do not intend to limit myself -to the exact construction shown at allpoints, as it maybe varied considerably without departing from thespirit of my invention.v For instance, l have shown the base pipes D Dcontinuous from end to end in full lines, but they may be made insections-a section to each down pipe C-as indicated in dotted lines inFig.

1, if preferred. Or if the boiler is to be used as a heater, the basetubes maybe dispensed with entirely by making suitable connections withthe radiator system of pipes.

What I claim as new isl'. The combination in a generator, ofca series ofhorizontal rows of bent tubes having their lower ends connected to therear portion of the generator and their upper ends connected to a seriesof headers arranged close together and horizontally and transversely ofthe furnace and forming a closed wall thereof, said headers havingianges and openings to connect each header with the adjacent headers,and all the tubes of each horizontal row being connected to the sameheader, substantially as described.

2. The combination in a generator, of a series of headers arranged in avertical plane, a series of headers arranged in a horizontal plane andthe members of each series being arranged close together to form aclosed wall of the furnace and smoke passage and communicating neartheir ends, both series transversely of the generator, and a series ofhorizontal rows of bent tubes connecting said headers, all the tubes ofeach horizontal row being connected to the same pair of headers,substantially as described.

3. The combination in a generator, of a series of rear headers arrangedin a vertical plane, a series of` front headers arranged 1n a horizontalplane, and the members of each series being arranged close together toform a closed wall of the furnace and smoke passage and communicatingnear their ends, both series transversely of the generator, and a seriesof horizontal rows of bent tubes having their lower ends entering thevertical sides of the rear headers, and their upper ends entering theunder sides of the front headers, and all the tubes of each horizontalrow being connected to the same pair of headers, substantially asdescribed. j

4. The combination in a steam generator, of, a series of upper tubularheaders arranged in a horizontal plane, a corresponding series of lowerheaders arranged in a vertical plane and both transversely of thegenerator, a series of bent tubes connecting said headers, a pair ofbase tubes connected to the rear headers, and a series of pairs ofvertical tubes connected to the opposite ends of the upper headers, eachupper header having a connection with the base tubes by a pair ofvertical tubes, independently of the others, substantially as described.

5. The combination in a generator and with the horizontal series oftransverse headers B, the curved tubes A and base tubes D D',connections between the base tubes and the lower ends of the curvedtubes of a series of palrs of down tubes C connecting each of saidheaders to the base tubes by an independent connection, substantially asdescribed.

6. The combination in a generator, of the horizontal series of headersB, the vertical series of headers B', the bent tubes A ruuning from oneseries of headers to the other, the base pipes D D connected with therear series of headers, and a series of pairs ot' down tubes Cconnecting each top header with the base pipes independently of theother headers, substantially as described. b 7. The combination in asteam generator, of avertical series of headers B', a horizontal seriesot headers B, curved tubes A connecting said two series of headers, adrum I arranged at the end of the horizontal series and connected withboth series, pipes D D' connected with the Vertical series of headers, aseries of pairs of pipes C connecting the horizontal series of headersto the pipes DD', each upper header being connected to the pipes D by aseparate pair of pipes, and a casing P between the pipes C and thefurnace, substantially as described. i

8. The combination of a series of upper headers B, arranged in ahorizontal plane, a corresponding series of lower headers B ar ranged ina vertical plane and both series set transversely of the furnace,horizontal rows of tubes A, each tubeliaving one of its ends turnedupward and connecting the two series of headers, all the tubes in eachhorizontal row entering one header in the vertical series and theirLip-turned ends entering a header in the horizontal series, a drum Iarranged at the end of the horizontal series of headers and connectedwith both series, pipes D D connected with the vertical series ofheaders, a seriesot pairs of pipes C connecting the horizontal series ofheaders to the pipes D D' each header of the upper series beingconnected to the pipes D D by a separate pair of said pipes C, Walls Nand casing P between the pipes C and furnace, the bridge K at the end ofthe furnace, and plates J J for directing the currents of the productsof eoinbustion, all constructed and arranged substantially as shown anddescribed.

In testimony whereof I aix my signature, in presence of two witnesses,this 15th day of April, 1893.

DAVID BIRDSALL. Witnesses:

JOHN C. INWRIGHT, WALTER K. BIRDsALL.

